1. French Committee for IYA 2009
An international network of observation for the International Year of Astronomy
J.-E. Arlot, A. Vienne, A.-C. Levasseur-Regourd
French Committee for IYA 2009
Athens, CAP2007
2007, October 10th

2. An opportunity
The equinox on Jupiter will take place in and the French committee for IYA09 will take this opportunity to propose coordinated observations gathered on a unique Internet site providing analysis and global results.
Athens, CAP2007
2007, October 10th

3. The events
The equinox on Jupiter will occur in 2009, allowing the occurrence of many events such as eclipses of the Galilean satellites by the planet Jupiter, occultations and transits and also mutual phenomena among the satellites themselves.
Athens, CAP2007
2007, October 10th

4. When do occur these events?
They occur when the planetocentric declination of the Sun and the Earth become zero: it is the equinox on the planet
Athens, CAP2007
2007, October 10th

5. These events are spectacular for everyone.
Athens, CAP2007
2007, October 10th

6. Observations of these events
These events are very easily observable, even with a small telescope and a numerical camera, since the Galilean satellites are very bright.
These events are spectacular since the satellites will disappear within a few seconds.
Athens, CAP2007
2007, October 10th

7. Case of mutual event
We will record the quantity of light received from the implied satellites depending on time in UTC within an accuracy of 0.1 second of time
Athens, CAP2007
2007, October 10th

8. Observations worldwide
We propose:
- that these events be observed worldwide by
amateur astronomers, students, pupils
- that they send their observation to a central web site
which will propose to every observer
- an analysis of his observation
- provides a data base of all the observations.
Athens, CAP2007
2007, October 10th

9. The Galilean satellites
Many explanations could be provided as on the Galilean satellites themselves (physics and dynamics studied through the observation of such events).
They are among the most interesting bodies (with volcanoes, ice,…) of the solar system, some possibly suitable for life (Europa).
Athens, CAP2007
2007, October 10th

10. History of astronomy
These bodies allow to recall the history of astronomy: the Galilean satellites were the first celestial objects extensively observed from Earth and they became the first reliable clock available for measuring longitudes
They allowed to measure the light speed.
Athens, CAP2007
2007, October 10th

11. Results and publications
At the end of the observational campaign, the results will be emphasized and the scientific benefits from these observations will be explained and published.
Pedagogic material will be made from observations by students and pupils (determination of light speed,…)
Scientific results will be published using amateur astronomers data (IMCCE has the experience of such an association)
Athens, CAP2007
2007, October 10th

12. Conclusion
We must use the opportunity of the Jovian equinox occurring only every 6 years and occurring in 2009.
We should make a pedagogical action with a worldwide echo.
Athens, CAP2007
2007, October 10th